Motion checking device.



BATENTED JAN. 21. 1908.

0. P. PBESSO N.

MOTION CHECKING DEVICE.

nruonxon run we. 24. 1905.

v Y Otto FT Per sson,

Y PATENTED JAN. 21, 1908.

O. P. PERSSON.

MOTION CHECKING DEVICE.

nrmouron FILED we.

2 SHEETS-S11E3 2.

Wibne sge s' 0. P. PERSSON.

MOTION CHECKING DEVICE.

APYLIOA'IION FILED AUG. 24. 1905.

PATENTED JAN. 21, 1908.

3 SHEETS-SHEET 3.

Inventor. Otto E Per-$501 7 Amy UNITED STATES PATENT OFFICE.

OTTO F. PERSSON, OF LYNN, MASSACHUSETTS. ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

MOTION CHECKING DEVICE.

Specification of Letters Patent.

- Patented Jan. 21, 1908.

Application filed August 24' 1905. Serial No. 275.597.

To all whom it may concern.

Be it known that I, OTTO F. PERSSON, a

- citizen of the United States, residing at l t-nu,

county of Essex, and State of Massachusetts, have invented certain new and useful Improvements in Motion (hocking Devices, of which'the followin is a specification.

In certain steering c rocks with which I am familiar various types of gearing, such as Level gears, a worm and segment, and a rack and pinion, are employed to transmit motion from the steering post or column to the steering wheels of the vehicle. With such gearing one tooth of one of the members engages at all times between two teeth or threads, as the case may be, of the other member, there being a line contact between the teeth. All of the shocks transmitted from the steering wheels are caused to act on the tooth of one member and either of the. two engaging -teeth of the other member, depending upon the direction in which the shock from the wheels :u'ts. Since the bearing surfaces of the two engaging teeth make simply a line contact, and is therefore very limited in area, it follows that the shocks produce rapid wear ofthc teeth, so that a serious back-lash in the gearing sooner or later results. As thegreatcr part of the travel is straightahead the central portions of the gearing suffer the most from shocks, and buck-lash at this point develops rapidly so that steering rendered diilicult and dangerous, espc-.

chilly for high speeds. Iii-some constructions attempts have been made to compensate for this wear by using an adjustable eccentric bushing,'or other means, for one or both members of the gearing so that as the teeth wear the mcmlwrs can be readjusted. This provides only a temporary cure for the evil and readjustment ol the parts has to be resorted to time and again, and sooner or later renewal of parts is necessary. Experience demonstrates that none of these steering rho-"ksare entirely satisfactory, especially after having been in use for a short time. is objcclionfldc. and moreover. the adjusting means renders the apparatus expensive to manufacture and maintain.

The object of nrv invention is to overcome the objections above referred to, and to pro- \tdfl a motion-cliccknig device of improved A mush-action requiring adjustnusnt i I l construction that is simple and substantial in character and com prises few parts which are of minimum size and weight.

In carrying out my invention, I employ a non-rotatable member or actuator which is reciprocated or moved longitudinally by the steering post. orcolumn and a second member rotated by the first and transmitting motion therefrom to the steering wheels of the vehicle. These members are arranged one within the other, the outer one being rifled and the inner one provided with spiral projections or threads which make a working iit with the rifles or grooves of the outer member whereby rotary motion is impartedto one by simple rectilinear movement of the other. The pitch of the threads or grooves is coarse so as to obtain the desired range of rotary movement for a given longitudinal movement of the actuator without requiring too great a power for the steering operation, and this without permitting the rotary member to transmit wheel strains to the hand of the operator. The number of threads is preferably small so that they can be made with large and substantial dimensions, as for instance with an inner member of about two and. ihrcwquarters inches (lirameter, I employ four evenly dis laced threads or spirals of about onc-hal inch depth. Hence with threads of say live inches in lengtlui the total area of bearing surface to take thethrust in one direction is about ten square inches, which is extremely liberal considering the work the threads are intended to do.' The outer member being rilled to lit the inner member, it also will have the same form oi bearing surface.

In order to "prevent the longitudinally movable member from rotating and also to assist in taking the shocks transmitted by the steering wheels, a frame or casing rigidly supported on soinc part of the vehicle is provided in '.'.'bicb-thc two members of the check arc unrelated. Between the frame and the longitutii ially-movable member is provided one r more loi'igitudinal splines or projections which litsor lit in a guidcway or ways of the other part, their function being to guide the movements of the reciprocatingmemberbutmore particularly to take the.

blows im 'iartedto it. For this latter purbearing surfaces.

faces of the splines engaging therewith are made amply large so that they can take the blows without any material wear. In a check having an inner member of the dimension above referred to, I employ two splines which are each about one-half inch in width and about five inches long, so that the total bearing surface of the splines or the guideways is ten square inches. In practice I have found this area to be satisfactory. If desired. however, more splines and guideways may be employed so as to increase the The figures which I. have used to illustrate the area of the tearing surfaces between the threads and rifles of the two relatively rotatable members of the check, and between the spline and grooveways, are fairly representative of actual coriditions. They can be changed, however, to suit an y given re uirement, but in every case provision for a maximum area of bearing surface is of paramount importance. The splines are arranged at diametricnl y'o' poslte points. It will be noted that the s ines on the re iprocating member are para lel to the axis of the rotating member or at right angles to its plane of rotation and hence have a maximum effect in preventing rotation of said reciprocating member.

Any suitable mechanism maybe employed to actuate the reciprocating member, that mechanism being preferable which requires the least exertion on the part of the operator. According to one construction I employ a rack and pinion between the steering column and the said member. The steering column is supported at its lower end by the frame o casing of the check and keyed thereto is a pinion meshing with a rack provided on the said member. The meshing teeth of the pinion and the rack, while having only a line contact are not subject to road strains since they are absorbed by the splines and guideways. For this reason there is no reverse motion or shock transmitted to the hand or steering wheel on the column. This irreversibility of movement is more strictly true in s aking of the strains due to sudden sllocri from the road wheels. By reason of the coarseness of the rifles and threads of the relatively rotatable elements of the check, the sudden shocks tend to cause the elements to rotate together, but the s lines prevent this. and the arts are heir rigid. With more contiuuer strains, however, such as produced by the wheels entering rats in the road ay while they are held at an angle to the latter, the rotatable element will move and cause the reciprocating, member or actuator to yield gradually and sufficiently to permit the wheels to aline with the ruts; otherwise, destructive strains might be brought to bear upon the wheels and other parts.

W'hile I have described the invention as applied to a self-propelled vehicle it is to be understood that the invention is not so limited since it may be used for other purposes where it is desirable to prevent strains on one part from being transmitted to another. Instead of dividing the easing into two parts on a. horizontal plane it may be made in a single piece with either one or two detachable heads.

trate one embodiment of the invention, Figure 1 is a front,elevation of the steeringchcckand coliiinn, the latter being partly broken away; Fig. 2 is a longitudinal section of the check showing parts in plan; Fi 3 is a central transverse section of the chec Sig. 4 isa longitudinal section of the check showing modified features of construction adapting it for tiller or lever steeringyand Fig. 5 is a plan of an automobile partly broken away with the check applied thereto.

Referring to the drawings, 1 represents a two-part casing or supporting frame for the movable members of the steering check, the parts being secured together by bolts 2. ()n the casing are arranged laterally projecting lugs 3, shown in Fig. 3 by means of which the check is mounted on the vehicle frame. 011 the upper half offhe frame is formed a vertical tubular extension 4 reinforced by webs The lower part is irovided with a short tubular extension 6, t e latter extension forming a step-bearing for the steering post or column 7, and the upper extension a guide-bearing therefor. The tubular extensions are arranged centrally between the ends of the frame at one side thereof and extend with their common axis at right angles to the axis of the casing or frame 1. \Yithin the casing is mounted a rotatable member or screw 8, which is provided at its end with journals 9, seated in alined journal lmarings 10. These journal bearings engage shoulders on the rotatable member and prevent it from being moved longitudinally due to any cause. Surrounding and engaging the screw is a non-rotatable reciprocating member or nut 11 which serves as an actuator to rotate the screw. The nut is rilled or grooved and the. threads or projections 12 of the screw make a good working fit with the rifles or grooves of the nut. The rifles or grooves of the not are of very coarse pitch so that by a reciprocating movement of the nutthe screw is rotuted. The nearer straight these rifles or grmves are, while still being capablepf performing their intended function of turning the screw, the better will be thercsults secured as there will be less tendency for the screw to impart longitudinal movement to the nut, due to shocks rcceivml from themed wheels.

l border to prevent the nut from rotating,

In the accompanying drawings which illusthe same is provided with one or more longi tudinally and radially extending projections or splines 13, which engage in grooves or guideways 14 in the frame or easing i. The. splines are adapted to transmit the shocks from the nutto the stationary and rigid frame or casing carried by thevehicle frame or other so port. Instead of locating the splines in tie position shown they may be located at other points. Where the casing divided into two principal parts they may be displaced by 90. When the casing is made in one'piece with one or more detachable heads they may be situated wherever it is the most convenient. It will be observed thatthese splines and guideways are made with large substantial surfaces so that they can take the shocks transmitted from the wheels without producing appreciable wear. This is also true with respect to the threads and grooves of the screw and nut.

To reduce the length of the check to a minimum, the bearings 10 which are located in the planeof division of the parts or" the all easing, are. tubular projections extending inwardly from the ends of the easing. and over these the nut is adapted to telescope as itmoves to and from its central position. At or "-ml of the srrew, the journal extendml beyond theend of the casing and squared to receive an arm or crank 15 that transmits motion to the steering wheels. The two journals 9 are of the same length so that the screw can be turned end for end in order to locate the arm atone side of the frame or the other to adapt the check for location on either side of the vehicle body.

The check-may be used for wheel or tiller steering as desired. In wheel steering. one revolution of the. steering wheel more or loss may be employed to move the road wheels from one extreme angular position to the other. Ordinarily one revolution will be. the best as this gives the proper scnsitivoness without the escrrise of too great power by the operator. In order to obtain this relation between the hand wheel and the nut 11, a rack and pinion connection is employed having relatively wide faces. The steering post is preferably a tube having keyed in its lower end a stub shaft 16, Fig. 3, and on the shaft is secured a pinion 17 that meshes with a reel-z ltsiormed ononoot'the projea-tions or splines 12; of the not. It will be observed that one of the splines not only prevents the nut from turning but also acts a part of the mechanism for moving it longitudinally. This is an important feature of the construction since it tends toward simplicity and also reduces the amount of machine work. 'lhe number of teeth on the pinion and its diameter may be varied as desired to obtain any de ree of sensitiveness. The stub shaft 16 is nollow so as to receive members 19 forming parts of the various regulating devices of the power a iparatus such as the throttling and spark adjusting devices.

As shown in Fig. l. the nut is in'midosition, this eor'respoiuling, to strai ht-aearl travel of the vehicle. By revo ving the hand-wheel 21') on the steeringmolunm half a revolution to the right the nut is caused to assume an extreme right-hand position, and oh 'iously the reverse movement occurs when the wheel is rotated half a revolution to the left. Any shocks that are transmitted from the road wheels to the screw are imparted to the walls of the rifles or grooves of the nut but the latter is prevented from rotation by means of the splines 13 that engagethe walls of the guideways. Thus, the sudden shocks produced by common obstructions and unevennesses in the roadbed cause no reversal of movement through the steering check. I The pitch of the rilles or grooves in the nut, l however. are so designed that the nut 11 will slowly yield or move longitudinally under a continued strain. from the rozul-wheel, such for instance as would be produced by the wheels dropping into rats in the roadwa while they are ataslight angle to the direction of the ruts. In this sense, the check is not absolutely irreversible. This provision for reversibility, however, is advantageous as it prolongs the life of the wheels and the axle construction. It will be seen that any suddentendencyof-the road-wheels to rotate the not will be resisted by the splines on the latter. The thrust tending to rotate the nut is in a direction parallel to the axisof the steering post or column. Under this condition there is absolutely no tendency for the nut to move longitudinally, and such being the case it follows that no strains will be imparted to the steering wheel, lever or tiller. 1n turn to be transmitted to the hand of the operator.

In tiller steering the angular movement of the tiller or hand lever nsnallv more limited than that of the wheel in. wheel steering, say about 90 degrees more or less. In order to adapt ache k for thisincthod of steering the rack and pinion is dispensed with and the following construction enu'iloyed. At the lower end of the steering post or column, Fig. 4, is secured a forked arm '21 which spans the out from one side, one arm of the fork extending above and the other below the nut. Each portion of the arm is bifurcated to )rovide par- By this arrangement, the angn lar movement of the arm is readilytranslated into rectilinear movement of the nut.

the dotted lines. In this C()I1sl.-l'lt0ii01l,'fl5 well as that involving the pinion and rack, the sudden shocks from the road wheels are taken up by the splines of the nut and the allel jaw: :22. which engage a b ock :21; pivl otcd on the nut.

The extreme steering positions are shown b)" walls of the grooves or guideways of the frame.

Referring to Fig. 5, represents the.

steering wheels and 25 the driving wheels of the vehicle.

usual manner by a drag link 28. One of the steering knuckles is provided with a rearwardly extending arm 2!) that connects with the crank 15 of the steering check by a link 30. Supported on the axles is the vehicle body 31 on which the steering check is mounted, the location of the latter being in the present instance on the left hand side.

In accordance with the provisions of the patent statutes, I have described the princi do of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof; butl desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

What I claim new, and desire to secure by Letters latent of the linited States, is,

1. In a motion checking device, the combination of a screw, a circular nut for imparting rotary motion to the screw, which is provided with projections on opposite sides of its axis, a circular frame )rovidcd with a plurality of grooves in which the projections are guided, a rack on the nut extending longitudinally thereof, a shaft supported by the frame with its axis perpendicular to the axis of the screw, and a pinion on the shaft; engaging the rack to impart longitudinal motion to the nut to rotate the screw.

2. In a motion checking device, the combination of a supporting frame 'or structure, a coarse pitch screw mounted thereon, a nut engaging the screw to impart rotation thereto, and journal bearings for the screw carried by the frame and over which the nut adapted to telescope as it, moves to and fro.

3. As an article of manufacture, a motion checking device comprising a two-part frame, and journal hearings extending inwardly from the ends of the frame and located in the plane of division thereof, said frame havtion checking device comprising a two-part frame, journal bearings extending inwardly from the ends of the frame and located in the plane of division thereof, said frame also having a guideway or groove formed therein which extends parallel to the axis of the journal bearings, a tubular extension or;

socket on one part of the frame. and ash-phearing on the other part. said extension and bearing being adapted to receive the steering post or column.

The steering wheels are mounted on short stub axles 26 having forwardly 1 extending arms 27 that are connected in the f bination of a separable casing or frame, two relatively rotatable elements mounted therein, opposed spline and groove connections between one of the elements and the frame for guiding the said element longitudinally and taking strains therefrom, a rack provided on one of the splines, a pinion meshing with the rack, and a device for actuating i the pinion to reci,' rocate the longitudinally movableelement.

6. In a steering gear for motor vehicles, a casing or frame made in two parts and provided with internal opposedguides, a sliding I nut made in the form of a sleeve with a coarse pitch thread, a rock-shaft having a thread meshing with that of the nut, bearl lugs for the shaft, a steering arm attached to the shaft, a rackJnoving with the nut, a pinion meshing with the rack, and a manually-actuated device for moving the pinion.

T. In a steering gtar for motor vehicles, the combination of movable elements, a shaft having a coarse'pitch screw, an arm connected with the movable elements and the shaft, a casing for the shaft divided into l two parts and provided with internal opposed guides in either part, a nut engaging the screw shaft to impart rotation thereto, and a post connected with the nut to reciprocate it and move the movable elements, said nut being provided with projections extending into said guides for reventi g motion from being transmitted em the movable elements to the post.

8. In a moti n-checking device, the combination of a hollow casing having longi i tudinal grooves in its inner surface, a nut provided with oppositely located splines on its icriphery extending the length of the nut and having large bearing surfaces in engagement with said grooves, a shaft passing through the nut, hearings on the casing for th shaft, a screw-thread on the shaft in enlongitudinally the shaft is rotated but a sudden foree tending to rotate the sha ft 1sunable to shift the nut, a rack: and pinion for l screw-shaft, and a shaftat-right angles to the axis of the nut and screwon which the pinion is mounted.

9. In a motion-checking device, the conimoving the nut lengthwiseg'to rotate the gagement with the nut, .the pitch of the thread being such that by moving the nut.

l hination of a rotatable shaft having acoarso pitch screw-thread thereon, a longitudinalli movable not engaging the threiuhthe pitc t of the thread being such that by moving the nut lengthwise the shaft is rotated while a sudden-force tending to rotate th( shaft is unahle to shift the not but a continued force will cau e the out to move sli'iwly', a casing in which the parts are mounted, oppositely lo- (nil-(l splines extending the length ut the nut and engaging grooves in the easin to form it 5. In a motion checking device, the comi large bearing surfaces at righting estotha ing shaf t which engages the rack to move the Him: the aet-uating shaft which prevent In witness whereof, I have hereunto set the rotation of the nut and receive shocks my hand this twenty-second day of August, 10

due to the forces tending to rotate the screw 1905. v shaft a longitudinal rack on the nut, an. 7 actuating shaft at right angles to the axis of OTTO PERSSOA the SCI'OW shaft, and a pinion on the actuat- Vltl'lCSSCS:

DUGALD MoK. McKILLoP,

nut along the grooves to rotate the shaft. SAMUEL TO NSEND STEWART. 

